The present invention relates to telescoping slide assemblies, and particularly to a slide assembly having three slide members and lock mechanisms for locking the slide members in various retracted and extended positions. More particularly, the present invention relates to a telescoping slide assembly that contains a mechanism for controlling locking and unlocking of a load-carrying slide member to and from an intermediate slide member during movement of those slide members toward extended positions relative to a stationary slide member.
A conventional telescoping slide assembly typically includes a stationary slide member, a load-carrying slide member, and an intermediate slide member. The intermediate slide member is positioned and configured to move the load-carrying slide member toward and away from the stationary slide member. The stationary slide member is typically mounted to a fixed frame to anchor the slide assembly. The frame could be a cabinet, a truck bed, or any other suitable platform. For example, it is known to use telescoping slide assemblies to slide heavy pieces of equipment into and out of a truck bed or a cabinet.
It is known to provide locking interconnections between each of the three slide members so that extension or retraction of the slide members relative to each other can be prevented. This allows a drawer or equipment rack mounted on a pair of telescoping slide assemblies to be extended outward in the extending direction and locked to maintain a desired extended position. Since these locking interconnections must generally be manually engaged and disengaged, separate manual unlocking actions are required before such a drawer or equipment can be extended. The use of a locking mechanism to prevent relative movement of two sliding tracks until manual release of the locking mechanism is known. See, for example, U.S. Pat. No. 4,200,342 to Fall. An automatic release mechanism for a telescoping slide assembly is disclosed in U.S. Pat. No. 5,405,195 to Hobbs.
Users of telescoping slide assemblies would welcome an assembly having load-carrying and intermediate slide members that would both move easily to fully extended positions relative to the stationary slide member even if the load supported by the load-carrying slide member was heavy or unbalanced. Such an assembly would be an improvement over conventional telescoping slide assemblies that are known, in some circumstances, to have a load-carrying slide member that moves to an extended position relative to an intermediate slide member before the intermediate slide member moves away from or leaves its retracted position in a stationary slide member and, as such, are difficult to operate to cause both of the load-carrying and intermediate slide members to be moved relative to the stationary slide member to fully extended positions.
According to the present invention, a telescoping slide assembly is provided for moving a load between a fully retracted position and a fully extended position. The telescoping slide assembly includes load-carrying, intermediate, and stationary slide members. The three members are movable relative to one another for extending and retracting the load-carrying and intermediate slide members relative to the stationary slide member. The telescoping slide assembly also includes a first slide lock arranged to couple the intermediate slide member to the load-carrying slide member and a second slide lock spaced apart from the first. The second slide lock is arranged to couple the intermediate slide member to the load-carrying slide member for movement independent of the first slide lock. An actuator is coupled to the first slide lock and configured to move the first slide lock from a locked position coupling the intermediate slide member to the load-carrying slide member to an unlocked position. The unlocked position of the first slide lock uncouples the intermediate slide member from the load-carrying slide member.
In preferred embodiments, first and second bushings are mounted in locking apertures of the first and second slide locks of the intermediate slide member. The first and second bushings each include a bushing aperture and a conical portion facing toward the bottom of the load-carrying member. First and second slide locks also include first and second vertical locking pins which are received by the first and second bushings as the telescoping slide assembly is being moved between fully retracted and extended positions.
To move the telescoping slide assembly toward a fully extended position, an operator must first use an actuating means to disengage the first locking pin from the first bushing aperture. Because the second locking pin has not yet been disengaged, the load-carrying and intermediate members are able to move together as a unit relative to the stationary slide member. Once the intermediate slide member has moved to a fully extended position, a third horizontal locking pin locks the intermediate slide member to the stationary slide member. This causes the second locking pin to ramp up the conical section of the second bushing and thus disengage the second locking pin from the bushing aperture. Now, the load-carrying member is allowed to move further toward a fully extended position relative to the intermediate slide member. During this process, the second locking pin must pass over the first bushing. In order to prevent the second locking pin from getting stuck within the bushing aperture, the second locking pin is designed to have a larger radius than the first locking pin and first bushing aperture. This allows an operator to be able to fully extend and retract the telescoping slide assembly without the intermediate slide member getting hung-up in a retained position within the stationary slide member. The actuator means must only be released once, therefore, to fully extend and retract the telescoping slide assembly. To accommodate for the larger radius of the second locking pin, the second bushing aperture must also have a larger radius than the first bushing aperture.
Once all three slide members are in their fully extended positions, an actuator may disengage the first locking pin locking the load-carrying slide member to the intermediate slide member. Upon this disengagement, the load-carrying member is now able to be fully retracted within the intermediate slide member. At this point, the third horizontal locking pin is urged to disengage and the intermediate and load-carrying slide members are able to move as a unit toward a fully retracted position within the stationary slide member.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.